Shell small, solid, cylindrical, somewhat oblong, with short spire and larval whorls projecting from the apex. About 4 whorls, with a subsutural channel bordered by a strong keel. Surface smooth, with growth lines barely visible, except for the subsutural channel that bears fine axial plicae. Aperture elongated, nearly as long as the body whorl, constricted above and dilated toward the base. Lip simple, straight, a little flexuous in the middle. Columella concave, with one fold and without umbilicus. The soft parts of this species are unknown. The animal in other species of this genus can retract completely into the shell; the foot is ovate in outline and lacks parapodia; the head shield is short, quadrangular, divided into two erected processes behind, near the base, where the eyes are situated.
common size :
up to 5.4 mm.
Acteocina mucronata shows a charasteristic mucronate apex, a concave part below the suture and plications at the upper part of the body whorl. The shell bears some resemblance to the Mediterranean species Retusa mamillata (Philippi, 1836), but differs in being somewhat bigger, less fragile, and more carinated and plicated at the suture. The closest species seems to be the west African Acteocina knockeri (Smith E.A.,1872), which is quite similar but does not occur further north of Mauritania.
BIOLOGY / ECOLOGY
No living specimens have been ever found; as other species of the family, it probably feeds upon foraminiferans.
this species seems to live in soft bottoms at a moderate depth.